1. Field of the Invention
The present invention relates to a process for the production of high-octane gasoline, which gasoline may contain no lead additive or very little lead additive. More particularly, the present invention is an integrated process involving paraffin dehydrogenation, olefin hydration, etheration and gasoline blending.
2. Prior Art and Related Disclosures
Gasoline compositions comprising dialkyl ethers have been disclosed in the prior art; for example, in U.S. Pat. No. 3,168,385 a motor fuel composition containing dialkyl ethers is disclosed. The fuel compositions disclosed in U.S. Pat. No. 3,168,385 include a saturated aliphatic hydrocarbon base stock in an amount from about 50% to about 90% by volume of the blend, a small amount of tetraethyl lead, a small amount of an alkyl ester of a C.sub.2 to C.sub.8 carboxylic acid, and a small amount of dialkyl ether. According to U.S. Pat. No. 3,168,385, preferably the ether is tertiary butyl methyl ether or diisopropyl ether.
There have not been a very large number of over-all processes disclosed for the production of etherated gasolines starting from the base feedstocks. However, an over-all process for the production of gasoline is disclosed in U.S. Pat. No. 3,482,952. According to the process disclosed in U.S. Pat. No. 3,482,952, a basic step in the over-all gasoline production process is the cracking of a hydrocarbon feedstock. The effluent from the cracking zone is fractionated into a plurality of streams, including at least a first stream and a second stream. The first stream boils in the range of about 15.degree. to 170.degree. F. and contains the major portion of the C.sub.4 to C.sub.6 tertiary olefins present in the cracking zone effluent. This first stream is contacted with a lower alcohol in the presence of an etheration catalyst to convert tertiary olefins in the first stream to ethers. Then the ether-containing first stream is combined with at least one hydrocarbon stream boiling in the range of about 15.degree. to 425.degree. F. to form a gasoline.
Methods for producing high-octane gasolines of reduced smog-forming tendencies in addition to those involving hydrocarbon cracking are desirable in view of the wide variety of gasoline-producing methods, including catalytic reforming, alkylation such as HF alkylation or H.sub.2 SO.sub.4 alkylation, hydrocracking, distillation of crude oil to obtain straight-run gasoline, and other methods.